JPH0816564B2 - Turbo refrigerator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a turbo refrigerator used for relatively large-scale air conditioning of a building or the like.

(Prior Art) Conventionally, a turbo compressor (T) having an impeller (F) rotated at high speed by a motor (M), as disclosed in JP-A-59-16146 and shown in FIG. 3, Hot water extraction pipe (Q)
The condenser (C) and the evaporator (E) that arranges the cold water take-out pipe (R), and the opening degree of the suction vane (B) arranged on the suction side of the impeller (F) is Adjustment is made via the controller (N) and the vane motor (G), and by changing the intake air volume accordingly, the refrigerating capacity matching the hot water or cold water load can be exhibited.

Further, in this type of turbo compressor (T), as its characteristics, as pointed out in the publication and shown in FIG.
When the head (H) to be secured between the suction side and the discharge side of the compressor (T) increases with respect to one vane opening (for example, D2), the suction pressure increases. When the air volume (V) is decreased for a while, the head (H) increases beyond a certain level, and the intake air volume (V) is extremely decreased, the pressure of the discharge gas, and thus the head (H), fluctuates up and down and becomes inoperable. Since a so-called surging phenomenon occurs, means for avoiding the surging phenomenon is provided. That is,
As shown in FIG. 3, a temperature detector (A) is installed in the hot water take-out pipe (Q), and if the hot water temperature is, for example, tc3 or more, the vane opening should not be set to D2 or less, and For example
If tc2 or more, D2 and D1 are set to the minimum vane opening so that the vane opening is not set to D1 or less, and the operation is performed at a larger opening than this so that the surging line (L) is not exceeded.

(Problems to be solved by the invention) With the above, the surging phenomenon can be avoided, but for example, when ensuring a hot water temperature of tc3 or more, the minimum vane opening becomes D2, and it cannot be made smaller than the opening D2. Therefore, even when the refrigerating capacity is sufficient at the opening D2 or less, the refrigerating capacity is exerted more than necessary, which causes a problem that low capacity operation cannot be covered. Further, in order to avoid this, by setting the vane opening based on the demand for refrigeration capacity, for example, by setting the opening to a small opening D3, the hot water take-out temperature can not be more than tc4, There arises a new problem that the upper limit of the take-out temperature is kept low.

Further, in general, when hot water is taken out, even if the same head is used, the condensation pressure, that is, the discharge pressure, is higher than the case where the cooling water is constantly circulated in the hot water take-out pipe (Q) in order to cool the condenser (C) with water. Is generally high, the hot water temperature to be taken out becomes high, or if the vane opening is narrowed down and the operation is performed at a low capacity, the temperature of the discharge gas before this occurs before the discharge gas pressure surging. Since the decomposition temperature (106 ° C.) of the Freon 11 which is a refrigerant normally used in a turbo refrigerator is reached, the vane opening control should be performed based on the temperature of the discharge gas.

The object of the present invention is to control the discharge gas temperature, adjust the vane opening so that the discharge gas temperature does not exceed the refrigerant decomposition temperature, and, if operated at a vane opening exceeding the required capacity, refrigerate the same. By correcting the increase in capacity by hot gas bypass, it is possible to provide a turbo chiller capable of taking out hot water of a relatively high temperature while performing operation matching the load.

(Means for Solving the Problem) Therefore, in the present invention, a turbo compressor (1) whose capacity can be controlled by changing the intake air flow rate by adjusting the opening of the suction vane (14), a condenser (2), and an expansion unit. In the structure in which the mechanism (3) and the evaporator (4) are sequentially connected to form a refrigeration cycle, and hot water is generated in the hot water take-out pipe (20) arranged in the condenser (2), the compression is performed. A hot gas bypass passage (5) for introducing the discharge gas discharged from the machine (1) into the evaporator (4) without performing the condensation action in the condenser (2) and the expansion action in the expansion mechanism (3). ) Is provided and a hot gas valve (6) whose opening degree is adjustable is provided in the bypass passage (5), while a temperature detector (7) for detecting the temperature of the discharge gas, and the temperature detector When the temperature detected in (7) reaches near the decomposition temperature of the refrigerant, The opening control means (8) for increasing the opening of the air conditioner (14) to increase the intake air volume, and for increasing the opening of the hot gas valve (6) to suppress the capacity increase due to the increase of the intake air flow. ) Has been decided.

(Operation) When operating at a certain vane opening, when the temperature of the discharge gas reaches near the decomposition temperature, the opening of the suction vane (14) is increased and the intake air volume is increased.
As a result, the temperature of the discharge gas is reduced. Further, at this increased vane opening, an upper limit value higher than the upper limit value of the take-out hot water temperature, which is limited based on the decomposition temperature at the vane opening before the increase, can be obtained. Can be increased.

On the other hand, although the refrigerating capacity tends to increase due to the increase in the opening degree of the suction vane (2), a part of the discharge gas passes through the hot gas bypass passage (6) and condenses and expands in the condenser (2). Since it is introduced into the evaporator (4) without undergoing the expansion action in (3), the increased amount can be suppressed by the reduction of the cooling effect in the evaporator (4).

(Example) What is shown in FIG. 1 is a motor (10) and a gearbox (11).
And a vane motor (1)
The turbo compressor (1) having a suction vane (14) whose opening is adjusted in 3) is provided with a condenser (2) having a hot water extraction pipe (20) on its discharge side and a float valve. A refrigeration cycle is configured by sequentially connecting an expansion mechanism (3) and an evaporator (4) provided with a cold water extraction pipe (40).

Then, the discharge gas discharged from the compressor (1) is condensed and expanded in the condenser (2) between the inlet of the condenser (2) and the inlet of the evaporator (4). A hot gas bypass passage (5) for introducing into the evaporator (4) without performing expansion action in the mechanism (3) is provided, and a hot gas valve (6) whose opening degree is adjustable in the bypass passage (5). ) Through.

Further, when the temperature detector (7) is provided in the discharge gas pipe (15) through which the discharge gas flows and the temperature detected by the temperature detector (7) reaches near the decomposition temperature of the refrigerant gas, An opening degree control means for increasing the opening degree of the vane (14) and increasing the opening degree of the hot gas valve (6) through a vane motor (13) to suppress the capacity increase due to the increase of the intake air volume. (8) is provided.

With the above configuration, as shown in FIG. 2, when the temperature of the discharge gas reaches near the decomposition temperature (tdn) when operating at a certain vane opening (for example, D2), the suction vane ( The opening degree of 14) is increased to D1, the intake air volume sucked into the impeller (12) is increased, and the temperature of the discharge gas is reduced. Further, since the vane opening is increased to D1, the head (H) can be increased up to the refrigerant decomposition temperature (tdn) at the opening D1, so that the refrigerant decomposition at the opening D1 increased from the take-out temperature tc3. It can be increased up to tc2 near the temperature.

On the other hand, although the refrigerating capacity tends to increase due to the increase in the opening degree of the suction vane (2), a part of the discharge gas passes through the hot gas bypass passage (6) and condenses and expands in the condenser (2). Since it is introduced into the evaporator (4) without undergoing the expansion action in (3), the increased amount can be suppressed by the reduction of the cooling effect in the evaporator (4).

As a result, the discharge gas temperature can be suppressed below the decomposition temperature of the refrigerant gas while the capacity operation matching the load can be performed, and the relatively high temperature hot water can be taken out to the hot water take-out pipe (20).

As described above, according to the present invention, when the discharge gas temperature reaches the decomposition temperature of the refrigerant gas at a certain vane opening, the opening of the suction vane (14) is increased to increase the intake air volume. Since the increase in the refrigerating capacity due to the increase in the intake air amount is corrected by the increase in the hot gas bypass amount due to the increase in the opening degree of the hot gas valve (6), the discharge gas is not discharged during the operation at a certain vane opening degree. Even if the temperature reaches near the decomposition temperature of the refrigerant gas, the discharge gas temperature can be suppressed below the decomposition temperature of the refrigerant gas, and further, the refrigerating capacity due to the increase in the vane opening can be suppressed and the load can be reduced. It is possible to perform matched capacity operation, and further, by increasing the vane opening, it is possible to obtain an upper limit higher than the upper limit of the hot water withdrawal temperature before the increase, and the hot water withdrawal pipe (20) has a relatively high temperature. Is the hot water put out taken.

[Brief description of drawings]

FIG. 1 is a refrigerant pipe system diagram of the refrigerator of the present invention, FIG. 2 is a diagram explaining the same operation, FIG. 3 is a refrigerant pipe system diagram of a conventional example, and FIG. 4 is a diagram explaining the problem. . (1) ...... Turbo compressor (2) ...... Condenser (3) ...... Expansion mechanism (4) ...... Evaporator (5) ...... Hot gas bypass passage (6) ...... Hot gas valve (7) ... … Temperature detector (8) …… Opening control means (14) …… Suction vane (20) …… Hot water extraction pipe

Claims (1)

[Claims] Claims: 1. A turbo compressor (1) whose capacity can be controlled by changing the amount of intake air by adjusting the opening of a suction vane (14), a condenser (2), an expansion mechanism (3) and an evaporator (4). In a turbo refrigerator in which hot water is generated in a hot water take-out pipe (20) arranged in the condenser (2), a discharge cycle discharged from the compressor (1) A hot gas bypass passage (5) is provided for introducing gas into the evaporator (4) without performing the condensation action in the condenser (2) and the expansion action in the expansion mechanism (3), and this bypass passage is provided. While a hot gas valve (6) whose opening degree is adjustable is provided in (5), a temperature detector (7) for detecting the temperature of the discharge gas and a temperature detected by the temperature detector (7) are When the temperature near the decomposition temperature of the refrigerant is reached, the opening of the vane (14) is increased to absorb the air. A turbo refrigerator having an opening control means (8) for increasing an air volume and increasing an opening degree of the hot gas valve (6) to suppress an increase in capacity due to an increase in the intake air volume. .